Heat-treating furnace



March 19, 1929. 1', LAURENCE 1,705,621

HEAT TREATING FURNACE Filed June 25, 192'? INVENTOR THOMAS J. LAURENCE, 0F DETROIT, MICHIGAN, ASSIGNOE TO CHRYSLER CORPORA- TION, OF HIGHLAND PARK, MICHIGAN, A CORPORATION OF DELAWARE.

HEAT-TREATING FURNACE.

Application filed June 25, 1927. "Serial 110. 201,531.

My invention relates to heat treating fur-- invention, there is no transference of car-.

riers from a conveyor to the furnace floor, but a smooth continuous movement of the trays thru the furnace along the tracks.

In the treating of cylindrical objects such as axles and cam shafts it is notgood practice to lay them on a carrier and pass them thru a heat treating furnace because the shaft will be unequally .heated, and therefore it is a further object of my invention to provide means inside the furnace to lift the shaft from the carrier so that the carrier acts as a pusher and rolls the shaft thru the furnace on the means, shown as ridges thus insuring an even distribution of heat around the entire circumference of the shaft,

due to its rotation.

Other objects of my invention are to provide srhall disconnected carrying elements that require small entrance and exit openings in the furnace walls so that the amount of heat allowed to escape thru these openings will be much less than in the case of other types of furnaces.

Another important object is to provide means for conducting objectionable fumes from the tempering liquid into the furnace that they may be consumed by combustion. It is still further desirable to provide a a means for returning the carrying elements to the front end of the furnace that they may be used over again.

The above stated objects of my invention will be more fully understood from the following specification and drawings, in which Fig. 1' is a side view of a heat treating furnace, partly in section showing a loading table and a tempering tank.

Fig. 2 is a sectional View on line 2-2'of Fig. 1.

Fig. 3 is a perspective View of one form of carrying block. 1

I have shown a heat treating furnace 10 having end. Walls 11' and 12 and an opening 13 for admitting parts to be treated and an opening 14: to allow the same arts to leave the furnace. Means for heating the furnace is shown at 16. There are two tracks 18 extending thru the furnace, 10 and for a short distance in front of the opening 13 to allow space for a pushing mechanism hereinafter described.

' Two ridges 40 extend thru the furnace parallel to and higher than the tracks 18.

Legs 24 and 25 support the furnace 10 from the floor, and, supported by the legs 24 is a gear 26 driven by a pinion 28 of a motor 30. The rotation of the gear 26 reciprocatesa 'link' 32 coupled to a lever arm 34, fulcrumed at 36, which lever reciprocates a pushing bar 38 on the tracks 18. l/Vork carrying blocks 20 are pushed thru the furnace. 10, on the tracks 18 by the pushing bar'38.

In operation,-there is placed on each track 18 a carrier block 20 and then a camshaft 22' is placed on these blocks. The movement of the pusher bar 38 forces this assemblage toward the opening 13.0f the furnace. and in so doing pushes all the blocks and shafts, in front, into and thru the furnace a distance corresponding to the movement of the bar 88. Upon entering the opening 13 the shafts'22 are lifted from the blocks 20 by the ridges 10. There are vertically extending prongs 21 on the blocks 20 adapted to push the shafts now resting on the ridges 40, thru the furnace 10. The forward movement of the shafts thru the furnace on the ridges 4.0, causes rotation of the shafts. There are openings 42 thru the floor of the furnace 10 at the discharge end of the tracks 18 so that the carrying blocks 20, after pushing the shafts 22 as far as is necessary, may drop down into chutes 11 and return, by gravity, to the front end of the v I I i We? furnace to be used over again.

A tank 48 containing a tempering liquid is placed beneath the discharge opening it. Inclined tracks 16 convey the shafts 22 from the opening 14 into the tank 48. A hood 50 surrounding the opening 14 and tracks 46 and extending down below the level of the tempering liquid conducts objectionable fumes from the liquid into the furnace where they are consumed.

It will be understood that the hood 50 closed by the liquid in the tank 48 serves a double purpose of conveying objectionable fumes into the furnace and closing the discharge opening thereof thus acting to retain heat within the furnace. The chutes 44 are tubular in cross section and bolted tightly beneath the openings 42 thus preventing any heat from leaking out at these openings. Therefore the opening 13 is the only open ing thru which heat may escape. A furnace of this type is very evenly heated thruout in an economical manner and'by causing the shafts 22 to roll, ,thru the furnace, the heat is very evenly distributed around them.

Obviously various changes may be made in the construction of the furnace and feed mechanism to adapt it to various shapes of objects to be heat treated without departing from the spirit of the invention as described in the preceding specification and claimed in the following claims.

What I claim is:

1. A device of-the class described comprising a furnace having'receiving and discharging openings, tracks within said furnace, work carrying blocks adapted to slide along said tracks, means for pushing said blocks along the tracks, openings thru the floor of said furnace beneath the discharging ends of said'tracks, and chutes beneath said openings adapted to return said. blocks to the receiving end of the furnace.

2. A device of the class described comprising a heat treating oven having receiving and discharging openings, tracks within said oven, separate work carrying blocks movable alon said tracks, means for sliding said blocks a ong said tracks, ridges within said oven to lift the work from said blocks,

means for rolling the work on said ridges,

and'openin s in thefloor of said oven beneath the ischarge end of said tracks to allow the blocks to fall out of the oven. v

3. A device of the class described, comprising a furnace having areceiving and a dis charging opening, tracks within said furnace, separate work carrying blocks adapted to be pushed thru the furnacenlong said tracks, ridges parallel to and higher than said tracks and adapted to lift the said work from said blocks, and means for rolling the work on-said ridges.

4;. A device of the class described, comprising a heat treating oven having a receiving and a discharging opening, tracks extending thru said oven and projecting beyond the receiving opening thereof, work carrying members adapted to slide along said tracks, means on the projected portion of said tracks to push said work carrying members toward the receiving opening of said oven, and means adapted to lift the work from said blocks whereby the work may be rotated while passing 'thru said furnace.

5. In a device of the class described, a furnace having receiving and discharging openings, tracks extending thru said furnaceywork carrying blocks adapted to slide along said tracks, ridges within the furnace and extending along said tracks and acting to lift the work from said blocks, and prongs on said blocks acting to push thework along said ridges.

6. A device of the class'described comprising a heat treating furnace having receiving and discharge openings, tracks within said furnace, separate work-carrying blocks on said tracks, means for sliding said blocks along said tracks, ridges within said furnace to lift the Work from said blocks, means for rolling the work along said ridges, openings beneath the end of said tracks, and means for returning said blocks from said openings to the receiving end of said oven.

7. A device of the class described comprising a heat'treating oven having receiving and discharging openings, means for receiving articles to be heated and for supporting them outside the oven adjacent the receiving opening aforesaid, and for thereafter moving them thru said oven from the receiving to the discharge opening thereof, and means extending'alongthe oven for lifting the articles being heated from said supporting means asthey enter the oven, and for supporting said members while they are being forced thru the oven by said supporting and moving means.

. THOMAS J. LAURENCE. 

